Everyone knows the accidental “reply all” can be devastating, but there’splenty of harm in the intentional “reply all.” An E-mail reply that’s terse, caustic, or cryptic might make sense to a single recipient (who knows the writer well) but it rarely translates to a broad audience. A regular habit can leave coworkers with a negative impression that’s “almost irreversible,” says Sandy Allgeier, author of The Personal Credibility Factor: How to Get It, Keep It, and Get It Back (If You’ve Lost It).